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1# SPDX-License-Identifier: GPL-2.0
2# ==========================================================================
3# Building
4# ==========================================================================
5
6src := $(srcroot)/$(obj)
7
8PHONY := $(obj)/
9$(obj)/:
10
11# Init all relevant variables used in kbuild files so
12# 1) they have correct type
13# 2) they do not inherit any value from the environment
14obj-y :=
15obj-m :=
16lib-y :=
17lib-m :=
18always-y :=
19always-m :=
20targets :=
21subdir-y :=
22subdir-m :=
23EXTRA_AFLAGS :=
24EXTRA_CFLAGS :=
25EXTRA_CPPFLAGS :=
26EXTRA_LDFLAGS :=
27asflags-y :=
28ccflags-y :=
29rustflags-y :=
30cppflags-y :=
31ldflags-y :=
32
33subdir-asflags-y :=
34subdir-ccflags-y :=
35
36# Read auto.conf if it exists, otherwise ignore
37-include $(objtree)/include/config/auto.conf
38
39include $(srctree)/scripts/Kbuild.include
40include $(srctree)/scripts/Makefile.compiler
41include $(kbuild-file)
42include $(srctree)/scripts/Makefile.lib
43
44ifndef obj
45$(warning kbuild: Makefile.build is included improperly)
46endif
47
48ifeq ($(need-modorder),)
49ifneq ($(obj-m),)
50$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.)
51$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.)
52endif
53endif
54
55# ===========================================================================
56
57# subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...)
58subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y)))
59subdir-modorder := $(sort $(filter %/modules.order, $(obj-m)))
60
61targets-for-builtin := $(extra-y)
62
63ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
64targets-for-builtin += $(obj)/lib.a
65endif
66
67ifdef need-builtin
68targets-for-builtin += $(obj)/built-in.a
69endif
70
71targets-for-modules := $(foreach x, o mod, \
72 $(patsubst %.o, %.$x, $(filter %.o, $(obj-m))))
73
74ifdef need-modorder
75targets-for-modules += $(obj)/modules.order
76endif
77
78targets += $(targets-for-builtin) $(targets-for-modules)
79
80# Linus' kernel sanity checking tool
81ifeq ($(KBUILD_CHECKSRC),1)
82 quiet_cmd_checksrc = CHECK $<
83 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
84else ifeq ($(KBUILD_CHECKSRC),2)
85 quiet_cmd_force_checksrc = CHECK $<
86 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
87endif
88
89ifneq ($(KBUILD_EXTRA_WARN),)
90 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $(KDOCFLAGS) \
91 $(if $(findstring 2, $(KBUILD_EXTRA_WARN)), -Wall) \
92 $<
93endif
94
95# Compile C sources (.c)
96# ---------------------------------------------------------------------------
97
98quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
99 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $<
100
101$(obj)/%.s: $(obj)/%.c FORCE
102 $(call if_changed_dep,cc_s_c)
103
104quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
105cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $<
106
107$(obj)/%.i: $(obj)/%.c FORCE
108 $(call if_changed_dep,cpp_i_c)
109
110genksyms = $(objtree)/scripts/genksyms/genksyms \
111 $(if $(KBUILD_SYMTYPES), -T $(@:.o=.symtypes)) \
112 $(if $(KBUILD_PRESERVE), -p) \
113 $(addprefix -r , $(wildcard $(@:.o=.symref)))
114
115# These mirror gensymtypes_S and co below, keep them in synch.
116cmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms)
117
118# LLVM assembly
119# Generate .ll files from .c
120quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@
121 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $<
122
123$(obj)/%.ll: $(obj)/%.c FORCE
124 $(call if_changed_dep,cc_ll_c)
125
126# C (.c) files
127# The C file is compiled and updated dependency information is generated.
128# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
129
130is-single-obj-m = $(and $(part-of-module),$(filter $@, $(obj-m)),y)
131
132ifdef CONFIG_MODVERSIONS
133# When module versioning is enabled the following steps are executed:
134# o compile a <file>.o from <file>.c
135# o if <file>.o doesn't contain a __export_symbol_*, i.e. does
136# not export symbols, it's done.
137# o otherwise, we calculate symbol versions using the good old
138# genksyms on the preprocessed source and dump them into the .cmd file.
139# o modpost will extract versions from that file and create *.c files that will
140# be compiled and linked to the kernel and/or modules.
141
142gen_symversions = \
143 if $(NM) $@ 2>/dev/null | grep -q ' __export_symbol_'; then \
144 $(cmd_gensymtypes_$1) >> $(dot-target).cmd; \
145 fi
146
147cmd_gen_symversions_c = $(call gen_symversions,c)
148
149endif
150
151ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
152# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
153ifdef BUILD_C_RECORDMCOUNT
154ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
155 RECORDMCOUNT_FLAGS = -w
156endif
157# Due to recursion, we must skip empty.o.
158# The empty.o file is created in the make process in order to determine
159# the target endianness and word size. It is made before all other C
160# files, including recordmcount.
161sub_cmd_record_mcount = \
162 if [ $(@) != "scripts/mod/empty.o" ]; then \
163 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
164 fi;
165recordmcount_source := $(srctree)/scripts/recordmcount.c \
166 $(srctree)/scripts/recordmcount.h
167else
168sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
169 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
170 "$(if $(CONFIG_64BIT),64,32)" \
171 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
172 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \
173 "$(if $(part-of-module),1,0)" "$(@)";
174recordmcount_source := $(srctree)/scripts/recordmcount.pl
175endif # BUILD_C_RECORDMCOUNT
176cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \
177 $(sub_cmd_record_mcount))
178endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
179
180# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
181# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
182# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
183
184is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(target-stem).o)$(OBJECT_FILES_NON_STANDARD)n),$(is-kernel-object))
185
186ifdef CONFIG_OBJTOOL
187$(obj)/%.o: private objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y))
188endif
189
190ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),)
191cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi)))
192endif
193
194# Built-in and composite module parts
195$(obj)/%.o: $(obj)/%.c $(recordmcount_source) FORCE
196 $(call if_changed_rule,cc_o_c)
197 $(call cmd,force_checksrc)
198
199# To make this rule robust against "Argument list too long" error,
200# ensure to add $(obj)/ prefix by a shell command.
201cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \
202 $(AWK) '!x[$$0]++ { print("$(obj)/"$$0) }' > $@
203
204$(obj)/%.mod: FORCE
205 $(call if_changed,mod)
206
207quiet_cmd_cc_lst_c = MKLST $@
208 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
209 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
210 System.map $(OBJDUMP) > $@
211
212$(obj)/%.lst: $(obj)/%.c FORCE
213 $(call if_changed_dep,cc_lst_c)
214
215# Compile Rust sources (.rs)
216# ---------------------------------------------------------------------------
217
218rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons
219
220# `--out-dir` is required to avoid temporaries being created by `rustc` in the
221# current working directory, which may be not accessible in the out-of-tree
222# modules case.
223rust_common_cmd = \
224 OBJTREE=$(abspath $(objtree)) \
225 RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \
226 -Zallow-features=$(rust_allowed_features) \
227 -Zcrate-attr=no_std \
228 -Zcrate-attr='feature($(rust_allowed_features))' \
229 -Zunstable-options --extern kernel \
230 --crate-type rlib -L $(objtree)/rust/ \
231 --crate-name $(basename $(notdir $@)) \
232 --sysroot=/dev/null \
233 --out-dir $(dir $@) --emit=dep-info=$(depfile)
234
235# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit
236# will be used. We explicitly request `-Ccodegen-units=1` in any case, and
237# the compiler shows a warning if it is not 1. However, if we ever stop
238# requesting it explicitly and we start using some other `--emit` that does not
239# imply it (and for which codegen is performed), then we would be out of sync,
240# i.e. the outputs we would get for the different single targets (e.g. `.ll`)
241# would not match each other.
242
243quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
244 cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $< $(cmd_objtool)
245
246define rule_rustc_o_rs
247 $(call cmd_and_fixdep,rustc_o_rs)
248 $(call cmd,gen_objtooldep)
249endef
250
251$(obj)/%.o: $(obj)/%.rs FORCE
252 +$(call if_changed_rule,rustc_o_rs)
253
254quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
255 cmd_rustc_rsi_rs = \
256 $(rust_common_cmd) -Zunpretty=expanded $< >$@; \
257 command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@
258
259$(obj)/%.rsi: $(obj)/%.rs FORCE
260 +$(call if_changed_dep,rustc_rsi_rs)
261
262quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
263 cmd_rustc_s_rs = $(rust_common_cmd) --emit=asm=$@ $<
264
265$(obj)/%.s: $(obj)/%.rs FORCE
266 +$(call if_changed_dep,rustc_s_rs)
267
268quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
269 cmd_rustc_ll_rs = $(rust_common_cmd) --emit=llvm-ir=$@ $<
270
271$(obj)/%.ll: $(obj)/%.rs FORCE
272 +$(call if_changed_dep,rustc_ll_rs)
273
274quiet_cmd_rustc_rs_rs_S = RSCPP $(quiet_modtag) $@
275 cmd_rustc_rs_rs_S = $(CPP) $(c_flags) -xc -C -P $< | sed '1,/^\/\/ Cut here.$$/d' >$@
276
277$(obj)/%.rs: $(obj)/%.rs.S FORCE
278 +$(call if_changed_dep,rustc_rs_rs_S)
279
280# Compile assembler sources (.S)
281# ---------------------------------------------------------------------------
282
283# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
284# or a file that it includes, in order to get versioned symbols. We build a
285# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
286# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
287#
288# This is convoluted. The .S file must first be preprocessed to run guards and
289# expand names, then the resulting exports must be constructed into plain
290# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
291# to make the genksyms input.
292#
293# These mirror gensymtypes_c and co above, keep them in synch.
294cmd_gensymtypes_S = \
295 { echo "\#include <linux/kernel.h>" ; \
296 echo "\#include <asm/asm-prototypes.h>" ; \
297 $(NM) $@ | sed -n 's/.* __export_symbol_\(.*\)/EXPORT_SYMBOL(\1);/p' ; } | \
298 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms)
299
300quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
301cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
302
303$(obj)/%.s: $(obj)/%.S FORCE
304 $(call if_changed_dep,cpp_s_S)
305
306ifdef CONFIG_ASM_MODVERSIONS
307
308# versioning matches the C process described above, with difference that
309# we parse asm-prototypes.h C header to get function definitions.
310
311cmd_gen_symversions_S = $(call gen_symversions,S)
312
313endif
314
315$(obj)/%.o: $(obj)/%.S FORCE
316 $(call if_changed_rule,as_o_S)
317
318targets += $(filter-out $(subdir-builtin), $(real-obj-y))
319targets += $(filter-out $(subdir-modorder), $(real-obj-m))
320targets += $(lib-y) $(always-y)
321
322# Linker scripts preprocessor (.lds.S -> .lds)
323# ---------------------------------------------------------------------------
324quiet_cmd_cpp_lds_S = LDS $@
325 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
326 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
327
328$(obj)/%.lds: $(src)/%.lds.S FORCE
329 $(call if_changed_dep,cpp_lds_S)
330
331# ASN.1 grammar
332# ---------------------------------------------------------------------------
333quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch]
334 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
335 $(basename $@).c $(basename $@).h
336
337$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
338 $(call cmd,asn1_compiler)
339
340# Build the compiled-in targets
341# ---------------------------------------------------------------------------
342
343# To build objects in subdirs, we need to descend into the directories
344$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ;
345$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ;
346
347#
348# Rule to compile a set of .o files into one .a file (without symbol table)
349#
350# To make this rule robust against "Argument list too long" error,
351# remove $(obj)/ prefix, and restore it by a shell command.
352
353quiet_cmd_ar_builtin = AR $@
354 cmd_ar_builtin = rm -f $@; \
355 $(if $(real-prereqs), printf "$(obj)/%s " $(patsubst $(obj)/%,%,$(real-prereqs)) | xargs) \
356 $(AR) cDPrST $@
357
358$(obj)/built-in.a: $(real-obj-y) FORCE
359 $(call if_changed,ar_builtin)
360
361# This is a list of build artifacts from the current Makefile and its
362# sub-directories. The timestamp should be updated when any of the member files.
363
364cmd_gen_order = { $(foreach m, $(real-prereqs), \
365 $(if $(filter %/$(notdir $@), $m), cat $m, echo $m);) :; } \
366 > $@
367
368$(obj)/modules.order: $(obj-m) FORCE
369 $(call if_changed,gen_order)
370
371#
372# Rule to compile a set of .o files into one .a file (with symbol table)
373#
374
375$(obj)/lib.a: $(lib-y) FORCE
376 $(call if_changed,ar)
377
378quiet_cmd_ld_multi_m = LD [M] $@
379 cmd_ld_multi_m = $(LD) $(ld_flags) -r -o $@ @$< $(cmd_objtool)
380
381define rule_ld_multi_m
382 $(call cmd_and_savecmd,ld_multi_m)
383 $(call cmd,gen_objtooldep)
384endef
385
386$(multi-obj-m): private objtool-enabled := $(delay-objtool)
387$(multi-obj-m): private part-of-module := y
388$(multi-obj-m): %.o: %.mod FORCE
389 $(call if_changed_rule,ld_multi_m)
390$(call multi_depend, $(multi-obj-m), .o, -objs -y -m)
391
392# Add intermediate targets:
393# When building objects with specific suffix patterns, add intermediate
394# targets that the final targets are derived from.
395intermediate_targets = $(foreach sfx, $(2), \
396 $(patsubst %$(strip $(1)),%$(sfx), \
397 $(filter %$(strip $(1)), $(targets))))
398# %.asn1.o <- %.asn1.[ch] <- %.asn1
399targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h)
400
401# Include additional build rules when necessary
402# ---------------------------------------------------------------------------
403
404# $(sort ...) is used here to remove duplicated words and excessive spaces.
405hostprogs := $(sort $(hostprogs))
406ifneq ($(hostprogs),)
407include $(srctree)/scripts/Makefile.host
408endif
409
410# $(sort ...) is used here to remove duplicated words and excessive spaces.
411userprogs := $(sort $(userprogs))
412ifneq ($(userprogs),)
413include $(srctree)/scripts/Makefile.userprogs
414endif
415
416ifneq ($(need-dtbslist)$(dtb-y)$(dtb-)$(filter %.dtb %.dtb.o %.dtbo.o,$(targets)),)
417include $(srctree)/scripts/Makefile.dtbs
418endif
419
420# Build
421# ---------------------------------------------------------------------------
422
423$(obj)/: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \
424 $(if $(KBUILD_MODULES), $(targets-for-modules)) \
425 $(subdir-ym) $(always-y)
426 @:
427
428# Single targets
429# ---------------------------------------------------------------------------
430
431single-subdirs := $(foreach d, $(subdir-ym), $(if $(filter $d/%, $(MAKECMDGOALS)), $d))
432single-subdir-goals := $(filter $(addsuffix /%, $(single-subdirs)), $(MAKECMDGOALS))
433
434$(single-subdir-goals): $(single-subdirs)
435 @:
436
437# Descending
438# ---------------------------------------------------------------------------
439
440PHONY += $(subdir-ym)
441$(subdir-ym):
442 $(Q)$(MAKE) $(build)=$@ \
443 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \
444 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) \
445 $(filter $@/%, $(single-subdir-goals))
446
447# Add FORCE to the prerequisites of a target to force it to be always rebuilt.
448# ---------------------------------------------------------------------------
449
450PHONY += FORCE
451
452FORCE:
453
454targets += $(filter-out $(single-subdir-goals), $(MAKECMDGOALS))
455targets := $(filter-out $(PHONY), $(targets))
456
457# Read all saved command lines and dependencies for the $(targets) we
458# may be building above, using $(if_changed{,_dep}). As an
459# optimization, we don't need to read them if the target does not
460# exist, we will rebuild anyway in that case.
461
462existing-targets := $(wildcard $(sort $(targets)))
463
464-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
465
466# Create directories for object files if they do not exist
467obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets))))
468# If targets exist, their directories apparently exist. Skip mkdir.
469existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets))))
470obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs)))
471ifneq ($(obj-dirs),)
472$(shell mkdir -p $(obj-dirs))
473endif
474
475.PHONY: $(PHONY)
1# SPDX-License-Identifier: GPL-2.0
2# ==========================================================================
3# Building
4# ==========================================================================
5
6src := $(obj)
7
8PHONY := $(obj)/
9$(obj)/:
10
11# Init all relevant variables used in kbuild files so
12# 1) they have correct type
13# 2) they do not inherit any value from the environment
14obj-y :=
15obj-m :=
16lib-y :=
17lib-m :=
18always-y :=
19always-m :=
20targets :=
21subdir-y :=
22subdir-m :=
23EXTRA_AFLAGS :=
24EXTRA_CFLAGS :=
25EXTRA_CPPFLAGS :=
26EXTRA_LDFLAGS :=
27asflags-y :=
28ccflags-y :=
29rustflags-y :=
30cppflags-y :=
31ldflags-y :=
32
33subdir-asflags-y :=
34subdir-ccflags-y :=
35
36# Read auto.conf if it exists, otherwise ignore
37-include include/config/auto.conf
38
39include $(srctree)/scripts/Kbuild.include
40include $(srctree)/scripts/Makefile.compiler
41include $(kbuild-file)
42include $(srctree)/scripts/Makefile.lib
43
44# Do not include hostprogs rules unless needed.
45# $(sort ...) is used here to remove duplicated words and excessive spaces.
46hostprogs := $(sort $(hostprogs))
47ifneq ($(hostprogs),)
48include $(srctree)/scripts/Makefile.host
49endif
50
51# Do not include userprogs rules unless needed.
52# $(sort ...) is used here to remove duplicated words and excessive spaces.
53userprogs := $(sort $(userprogs))
54ifneq ($(userprogs),)
55include $(srctree)/scripts/Makefile.userprogs
56endif
57
58ifndef obj
59$(warning kbuild: Makefile.build is included improperly)
60endif
61
62ifeq ($(need-modorder),)
63ifneq ($(obj-m),)
64$(warning $(patsubst %.o,'%.ko',$(obj-m)) will not be built even though obj-m is specified.)
65$(warning You cannot use subdir-y/m to visit a module Makefile. Use obj-y/m instead.)
66endif
67endif
68
69# ===========================================================================
70
71# subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...)
72subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y)))
73subdir-modorder := $(sort $(filter %/modules.order, $(obj-m)))
74
75targets-for-builtin := $(extra-y)
76
77ifneq ($(strip $(lib-y) $(lib-m) $(lib-)),)
78targets-for-builtin += $(obj)/lib.a
79endif
80
81ifdef need-builtin
82targets-for-builtin += $(obj)/built-in.a
83endif
84
85targets-for-modules := $(foreach x, o mod, \
86 $(patsubst %.o, %.$x, $(filter %.o, $(obj-m))))
87
88ifdef need-modorder
89targets-for-modules += $(obj)/modules.order
90endif
91
92targets += $(targets-for-builtin) $(targets-for-modules)
93
94# Linus' kernel sanity checking tool
95ifeq ($(KBUILD_CHECKSRC),1)
96 quiet_cmd_checksrc = CHECK $<
97 cmd_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
98else ifeq ($(KBUILD_CHECKSRC),2)
99 quiet_cmd_force_checksrc = CHECK $<
100 cmd_force_checksrc = $(CHECK) $(CHECKFLAGS) $(c_flags) $<
101endif
102
103ifneq ($(KBUILD_EXTRA_WARN),)
104 cmd_checkdoc = $(srctree)/scripts/kernel-doc -none $(KDOCFLAGS) \
105 $(if $(findstring 2, $(KBUILD_EXTRA_WARN)), -Wall) \
106 $<
107endif
108
109# Compile C sources (.c)
110# ---------------------------------------------------------------------------
111
112quiet_cmd_cc_s_c = CC $(quiet_modtag) $@
113 cmd_cc_s_c = $(CC) $(filter-out $(DEBUG_CFLAGS) $(CC_FLAGS_LTO), $(c_flags)) -fverbose-asm -S -o $@ $<
114
115$(obj)/%.s: $(src)/%.c FORCE
116 $(call if_changed_dep,cc_s_c)
117
118quiet_cmd_cpp_i_c = CPP $(quiet_modtag) $@
119cmd_cpp_i_c = $(CPP) $(c_flags) -o $@ $<
120
121$(obj)/%.i: $(src)/%.c FORCE
122 $(call if_changed_dep,cpp_i_c)
123
124genksyms = scripts/genksyms/genksyms \
125 $(if $(1), -T $(2)) \
126 $(if $(KBUILD_PRESERVE), -p) \
127 -r $(or $(wildcard $(2:.symtypes=.symref)), /dev/null)
128
129# These mirror gensymtypes_S and co below, keep them in synch.
130cmd_gensymtypes_c = $(CPP) -D__GENKSYMS__ $(c_flags) $< | $(genksyms)
131
132quiet_cmd_cc_symtypes_c = SYM $(quiet_modtag) $@
133 cmd_cc_symtypes_c = $(call cmd_gensymtypes_c,true,$@) >/dev/null
134
135$(obj)/%.symtypes : $(src)/%.c FORCE
136 $(call cmd,cc_symtypes_c)
137
138# LLVM assembly
139# Generate .ll files from .c
140quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@
141 cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -fno-discard-value-names -o $@ $<
142
143$(obj)/%.ll: $(src)/%.c FORCE
144 $(call if_changed_dep,cc_ll_c)
145
146# C (.c) files
147# The C file is compiled and updated dependency information is generated.
148# (See cmd_cc_o_c + relevant part of rule_cc_o_c)
149
150is-single-obj-m = $(and $(part-of-module),$(filter $@, $(obj-m)),y)
151
152# When a module consists of a single object, there is no reason to keep LLVM IR.
153# Make $(LD) covert LLVM IR to ELF here.
154ifdef CONFIG_LTO_CLANG
155cmd_ld_single_m = $(if $(is-single-obj-m), ; $(LD) $(ld_flags) -r -o $(tmp-target) $@; mv $(tmp-target) $@)
156endif
157
158quiet_cmd_cc_o_c = CC $(quiet_modtag) $@
159 cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $< \
160 $(cmd_ld_single_m) \
161 $(cmd_objtool)
162
163ifdef CONFIG_MODVERSIONS
164# When module versioning is enabled the following steps are executed:
165# o compile a <file>.o from <file>.c
166# o if <file>.o doesn't contain a __export_symbol_*, i.e. does
167# not export symbols, it's done.
168# o otherwise, we calculate symbol versions using the good old
169# genksyms on the preprocessed source and dump them into the .cmd file.
170# o modpost will extract versions from that file and create *.c files that will
171# be compiled and linked to the kernel and/or modules.
172
173gen_symversions = \
174 if $(NM) $@ 2>/dev/null | grep -q ' __export_symbol_'; then \
175 $(call cmd_gensymtypes_$(1),$(KBUILD_SYMTYPES),$(@:.o=.symtypes)) \
176 >> $(dot-target).cmd; \
177 fi
178
179cmd_gen_symversions_c = $(call gen_symversions,c)
180
181endif
182
183ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
184# compiler will not generate __mcount_loc use recordmcount or recordmcount.pl
185ifdef BUILD_C_RECORDMCOUNT
186ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
187 RECORDMCOUNT_FLAGS = -w
188endif
189# Due to recursion, we must skip empty.o.
190# The empty.o file is created in the make process in order to determine
191# the target endianness and word size. It is made before all other C
192# files, including recordmcount.
193sub_cmd_record_mcount = \
194 if [ $(@) != "scripts/mod/empty.o" ]; then \
195 $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
196 fi;
197recordmcount_source := $(srctree)/scripts/recordmcount.c \
198 $(srctree)/scripts/recordmcount.h
199else
200sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
201 "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
202 "$(if $(CONFIG_64BIT),64,32)" \
203 "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS)" \
204 "$(LD) $(KBUILD_LDFLAGS)" "$(NM)" "$(RM)" "$(MV)" \
205 "$(if $(part-of-module),1,0)" "$(@)";
206recordmcount_source := $(srctree)/scripts/recordmcount.pl
207endif # BUILD_C_RECORDMCOUNT
208cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), \
209 $(sub_cmd_record_mcount))
210endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
211
212# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory
213# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file
214# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
215
216is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y)
217
218$(obj)/%.o: objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y))
219
220ifneq ($(findstring 1, $(KBUILD_EXTRA_WARN)),)
221cmd_warn_shared_object = $(if $(word 2, $(modname-multi)),$(warning $(kbuild-file): $*.o is added to multiple modules: $(modname-multi)))
222endif
223
224define rule_cc_o_c
225 $(call cmd_and_fixdep,cc_o_c)
226 $(call cmd,checksrc)
227 $(call cmd,checkdoc)
228 $(call cmd,gen_objtooldep)
229 $(call cmd,gen_symversions_c)
230 $(call cmd,record_mcount)
231 $(call cmd,warn_shared_object)
232endef
233
234define rule_as_o_S
235 $(call cmd_and_fixdep,as_o_S)
236 $(call cmd,gen_objtooldep)
237 $(call cmd,gen_symversions_S)
238 $(call cmd,warn_shared_object)
239endef
240
241# Built-in and composite module parts
242$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
243 $(call if_changed_rule,cc_o_c)
244 $(call cmd,force_checksrc)
245
246# To make this rule robust against "Argument list too long" error,
247# ensure to add $(obj)/ prefix by a shell command.
248cmd_mod = printf '%s\n' $(call real-search, $*.o, .o, -objs -y -m) | \
249 $(AWK) '!x[$$0]++ { print("$(obj)/"$$0) }' > $@
250
251$(obj)/%.mod: FORCE
252 $(call if_changed,mod)
253
254quiet_cmd_cc_lst_c = MKLST $@
255 cmd_cc_lst_c = $(CC) $(c_flags) -g -c -o $*.o $< && \
256 $(CONFIG_SHELL) $(srctree)/scripts/makelst $*.o \
257 System.map $(OBJDUMP) > $@
258
259$(obj)/%.lst: $(src)/%.c FORCE
260 $(call if_changed_dep,cc_lst_c)
261
262# Compile Rust sources (.rs)
263# ---------------------------------------------------------------------------
264
265rust_allowed_features := new_uninit,offset_of
266
267# `--out-dir` is required to avoid temporaries being created by `rustc` in the
268# current working directory, which may be not accessible in the out-of-tree
269# modules case.
270rust_common_cmd = \
271 RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \
272 -Zallow-features=$(rust_allowed_features) \
273 -Zcrate-attr=no_std \
274 -Zcrate-attr='feature($(rust_allowed_features))' \
275 --extern alloc --extern kernel \
276 --crate-type rlib -L $(objtree)/rust/ \
277 --crate-name $(basename $(notdir $@)) \
278 --sysroot=/dev/null \
279 --out-dir $(dir $@) --emit=dep-info=$(depfile)
280
281# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit
282# will be used. We explicitly request `-Ccodegen-units=1` in any case, and
283# the compiler shows a warning if it is not 1. However, if we ever stop
284# requesting it explicitly and we start using some other `--emit` that does not
285# imply it (and for which codegen is performed), then we would be out of sync,
286# i.e. the outputs we would get for the different single targets (e.g. `.ll`)
287# would not match each other.
288
289quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
290 cmd_rustc_o_rs = $(rust_common_cmd) --emit=obj=$@ $<
291
292$(obj)/%.o: $(src)/%.rs FORCE
293 $(call if_changed_dep,rustc_o_rs)
294
295quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
296 cmd_rustc_rsi_rs = \
297 $(rust_common_cmd) -Zunpretty=expanded $< >$@; \
298 command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@
299
300$(obj)/%.rsi: $(src)/%.rs FORCE
301 $(call if_changed_dep,rustc_rsi_rs)
302
303quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
304 cmd_rustc_s_rs = $(rust_common_cmd) --emit=asm=$@ $<
305
306$(obj)/%.s: $(src)/%.rs FORCE
307 $(call if_changed_dep,rustc_s_rs)
308
309quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
310 cmd_rustc_ll_rs = $(rust_common_cmd) --emit=llvm-ir=$@ $<
311
312$(obj)/%.ll: $(src)/%.rs FORCE
313 $(call if_changed_dep,rustc_ll_rs)
314
315# Compile assembler sources (.S)
316# ---------------------------------------------------------------------------
317
318# .S file exports must have their C prototypes defined in asm/asm-prototypes.h
319# or a file that it includes, in order to get versioned symbols. We build a
320# dummy C file that includes asm-prototypes and the EXPORT_SYMBOL lines from
321# the .S file (with trailing ';'), and run genksyms on that, to extract vers.
322#
323# This is convoluted. The .S file must first be preprocessed to run guards and
324# expand names, then the resulting exports must be constructed into plain
325# EXPORT_SYMBOL(symbol); to build our dummy C file, and that gets preprocessed
326# to make the genksyms input.
327#
328# These mirror gensymtypes_c and co above, keep them in synch.
329cmd_gensymtypes_S = \
330 { echo "\#include <linux/kernel.h>" ; \
331 echo "\#include <asm/asm-prototypes.h>" ; \
332 $(NM) $@ | sed -n 's/.* __export_symbol_\(.*\)/EXPORT_SYMBOL(\1);/p' ; } | \
333 $(CPP) -D__GENKSYMS__ $(c_flags) -xc - | $(genksyms)
334
335quiet_cmd_cc_symtypes_S = SYM $(quiet_modtag) $@
336 cmd_cc_symtypes_S = $(call cmd_gensymtypes_S,true,$@) >/dev/null
337
338$(obj)/%.symtypes : $(src)/%.S FORCE
339 $(call cmd,cc_symtypes_S)
340
341
342quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@
343cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $<
344
345$(obj)/%.s: $(src)/%.S FORCE
346 $(call if_changed_dep,cpp_s_S)
347
348quiet_cmd_as_o_S = AS $(quiet_modtag) $@
349 cmd_as_o_S = $(CC) $(a_flags) -c -o $@ $< $(cmd_objtool)
350
351ifdef CONFIG_ASM_MODVERSIONS
352
353# versioning matches the C process described above, with difference that
354# we parse asm-prototypes.h C header to get function definitions.
355
356cmd_gen_symversions_S = $(call gen_symversions,S)
357
358endif
359
360$(obj)/%.o: $(src)/%.S FORCE
361 $(call if_changed_rule,as_o_S)
362
363targets += $(filter-out $(subdir-builtin), $(real-obj-y))
364targets += $(filter-out $(subdir-modorder), $(real-obj-m))
365targets += $(real-dtb-y) $(lib-y) $(always-y)
366
367# Linker scripts preprocessor (.lds.S -> .lds)
368# ---------------------------------------------------------------------------
369quiet_cmd_cpp_lds_S = LDS $@
370 cmd_cpp_lds_S = $(CPP) $(cpp_flags) -P -U$(ARCH) \
371 -D__ASSEMBLY__ -DLINKER_SCRIPT -o $@ $<
372
373$(obj)/%.lds: $(src)/%.lds.S FORCE
374 $(call if_changed_dep,cpp_lds_S)
375
376# ASN.1 grammar
377# ---------------------------------------------------------------------------
378quiet_cmd_asn1_compiler = ASN.1 $(basename $@).[ch]
379 cmd_asn1_compiler = $(objtree)/scripts/asn1_compiler $< \
380 $(basename $@).c $(basename $@).h
381
382$(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
383 $(call cmd,asn1_compiler)
384
385# Build the compiled-in targets
386# ---------------------------------------------------------------------------
387
388# To build objects in subdirs, we need to descend into the directories
389$(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ;
390$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ;
391
392#
393# Rule to compile a set of .o files into one .a file (without symbol table)
394#
395# To make this rule robust against "Argument list too long" error,
396# remove $(obj)/ prefix, and restore it by a shell command.
397
398quiet_cmd_ar_builtin = AR $@
399 cmd_ar_builtin = rm -f $@; \
400 $(if $(real-prereqs), printf "$(obj)/%s " $(patsubst $(obj)/%,%,$(real-prereqs)) | xargs) \
401 $(AR) cDPrST $@
402
403$(obj)/built-in.a: $(real-obj-y) FORCE
404 $(call if_changed,ar_builtin)
405
406#
407# Rule to create modules.order file
408#
409# Create commands to either record .ko file or cat modules.order from
410# a subdirectory
411# Add $(obj-m) as the prerequisite to avoid updating the timestamp of
412# modules.order unless contained modules are updated.
413
414cmd_modules_order = { $(foreach m, $(real-prereqs), \
415 $(if $(filter %/modules.order, $m), cat $m, echo $m);) :; } \
416 > $@
417
418$(obj)/modules.order: $(obj-m) FORCE
419 $(call if_changed,modules_order)
420
421#
422# Rule to compile a set of .o files into one .a file (with symbol table)
423#
424
425$(obj)/lib.a: $(lib-y) FORCE
426 $(call if_changed,ar)
427
428quiet_cmd_ld_multi_m = LD [M] $@
429 cmd_ld_multi_m = $(LD) $(ld_flags) -r -o $@ @$< $(cmd_objtool)
430
431define rule_ld_multi_m
432 $(call cmd_and_savecmd,ld_multi_m)
433 $(call cmd,gen_objtooldep)
434endef
435
436$(multi-obj-m): objtool-enabled := $(delay-objtool)
437$(multi-obj-m): part-of-module := y
438$(multi-obj-m): %.o: %.mod FORCE
439 $(call if_changed_rule,ld_multi_m)
440$(call multi_depend, $(multi-obj-m), .o, -objs -y -m)
441
442# Add intermediate targets:
443# When building objects with specific suffix patterns, add intermediate
444# targets that the final targets are derived from.
445intermediate_targets = $(foreach sfx, $(2), \
446 $(patsubst %$(strip $(1)),%$(sfx), \
447 $(filter %$(strip $(1)), $(targets))))
448# %.asn1.o <- %.asn1.[ch] <- %.asn1
449# %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
450# %.dtbo.o <- %.dtbo.S <- %.dtbo <- %.dtso
451# %.lex.o <- %.lex.c <- %.l
452# %.tab.o <- %.tab.[ch] <- %.y
453targets += $(call intermediate_targets, .asn1.o, .asn1.c .asn1.h) \
454 $(call intermediate_targets, .dtb.o, .dtb.S .dtb) \
455 $(call intermediate_targets, .dtbo.o, .dtbo.S .dtbo) \
456 $(call intermediate_targets, .lex.o, .lex.c) \
457 $(call intermediate_targets, .tab.o, .tab.c .tab.h)
458
459# Build
460# ---------------------------------------------------------------------------
461
462$(obj)/: $(if $(KBUILD_BUILTIN), $(targets-for-builtin)) \
463 $(if $(KBUILD_MODULES), $(targets-for-modules)) \
464 $(subdir-ym) $(always-y)
465 @:
466
467# Single targets
468# ---------------------------------------------------------------------------
469
470single-subdirs := $(foreach d, $(subdir-ym), $(if $(filter $d/%, $(MAKECMDGOALS)), $d))
471single-subdir-goals := $(filter $(addsuffix /%, $(single-subdirs)), $(MAKECMDGOALS))
472
473$(single-subdir-goals): $(single-subdirs)
474 @:
475
476# Descending
477# ---------------------------------------------------------------------------
478
479PHONY += $(subdir-ym)
480$(subdir-ym):
481 $(Q)$(MAKE) $(build)=$@ \
482 need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \
483 need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1) \
484 $(filter $@/%, $(single-subdir-goals))
485
486# Add FORCE to the prequisites of a target to force it to be always rebuilt.
487# ---------------------------------------------------------------------------
488
489PHONY += FORCE
490
491FORCE:
492
493targets += $(filter-out $(single-subdir-goals), $(MAKECMDGOALS))
494targets := $(filter-out $(PHONY), $(targets))
495
496# Read all saved command lines and dependencies for the $(targets) we
497# may be building above, using $(if_changed{,_dep}). As an
498# optimization, we don't need to read them if the target does not
499# exist, we will rebuild anyway in that case.
500
501existing-targets := $(wildcard $(sort $(targets)))
502
503-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
504
505# Create directories for object files if they do not exist
506obj-dirs := $(sort $(patsubst %/,%, $(dir $(targets))))
507# If targets exist, their directories apparently exist. Skip mkdir.
508existing-dirs := $(sort $(patsubst %/,%, $(dir $(existing-targets))))
509obj-dirs := $(strip $(filter-out $(existing-dirs), $(obj-dirs)))
510ifneq ($(obj-dirs),)
511$(shell mkdir -p $(obj-dirs))
512endif
513
514.PHONY: $(PHONY)